The next generation radio communication systems are expected to operate at much higher frequency when compared to the 3rd Generation (3G) and 4th Generation (4G) systems. Since a path loss of a radio signal is proportional to the square of its carrier frequency approximately, the signal attenuation at high frequency is much higher than at low frequency. As an example, the signal attenuation at 10 GHz could be 20 dB higher than that at 1 GHz.
In order to compensate for the increased attenuation at higher carrier frequency, the beam-forming technique is considered as one key component in the next generation systems. When many antenna elements of small antenna element size are integrated in a small antenna panel, it is possible to provide a much higher beam-forming gain than the 4G systems.
With such high beam-forming gain, inter-link interferences will become highly directional and thus the interference characteristics will become quite different from those in the 3G and 4G systems.
FIG. 1 shows an exemplary network scenario. As shown in FIG. 1, a Central Control Unit (CCU) 110 controls a cluster of Access Nodes (ANs) 121, 122, 123 and 124. Each of the ANs may serve one or more terminal devices, two of which are shown at 131 and 132. FIG. 1 also shows several, but maybe not all, radio links in this cluster: Link #1 from the terminal device 131 to the AN 121, Link #2 from the AN 121 to the terminal device 131, Link #3 from the AN 122 to the terminal device 132 and Link #4 (a backhaul link) from the AN 124 to the AN 122. For each of these links, the CCU 110 allocates radio resources for the link and generates a resource template indicating the resource allocation.
FIG. 2 shows an example of a resource template for a radio link, e.g., Link #1. The smallest grid in time (subframe) and frequency (subcarrier) is referred to as a Resource Element (RE). These REs may be assigned with different schedulabilities (or scheduling priorities), such that the AN 121 may determine which of these REs is/are to be scheduled for Link #1 based on the schedulabilities.
One solution is to design resource templates with schedulabilities that can mitigate the inter-link interferences in the cluster.